The present invention relates to a bearing device for a capstan shaft suitable for forming an extremely thin tape recorder.
In tape recorders, a flywheel is integrally formed with a capstan shaft so as to stabilize rotation of the capstan shaft and to drive the capstan shaft by means of the flywheel.
There is also provided a capstan bearing device for supporting the capstan shaft, and a device of this type is shown in FIG. 1, in which a capstan shaft 2 provided with a flywheel 1 is supported by a bearing member 3 and under this condition the top of the capstan shaft 2 may be inserted into a tape cassette 4.
In such construction, however, a securing portion of the flywheel 1 and the bearing member 3 occupy a comparatively large portion of the capstan shaft 2 in the axial direction thereof, so that it is difficult to form the tape recorder with a sufficiently thin configuration. In order to design a thin tape recorder, therefore, it is attempted to make the size of the bearing member 3 shorter in the axial direction. However, shortening the size of the bearing member increases the load on the bearing, increases electrical current consumption, increases the likelihood that the capstan shaft 2 will become loosened, and diminishes the durability of the tape recorder.
A device of the type described above is shown in FIG. 2, wherein the capstan shaft 2 provided with the flywheel 1 is supported by the bearing member 3 at the upper portion of the flywheel 1 and a part of the bearing member 3 is located to extend to within the tape cassette 4.
With a construction of this type however, in the case of a superminiature tape recorder, the cassette 4 and the magnetic tape will be located extremely close to the bearing member 3, so that oil from the bearing member 3 will adhere to the cassette or to the tape through the capstan shaft 2, and thus the cassette 4 will be damaged and become impossible to use.